Increase air flow into the shed by opening all the doors and windows and placing one or two large fans on the wall opposite of the largest door. Run the fans during the coolest part of the day, usually early morning and late evening, for four to five hours.
Create shade for the shed by attaching an awning to either the south or the west side of the shed. Locate the exterior wall studs of the shed by using an electronic stud-finding device. Attach the awning to the exterior shed studs using the hardware included with the awning and following the manufacturer's installation instructions.
Create even more shade for the shed by planting a small Norway maple tree on both the south and west sides of the shed. Dig a hole approximately 2 feet deep and 18 inches in diameter, using a spade shovel. Remove the small Norway maple from its container and set it gently into the hole. Fill the hole back in with dirt and tightly pack it into place using either the bottom of the shovel, or by stomping on it with your feet. Water the newly planted tree by laying a running garden hose directly over the filled in hole and letting it run for approximately 10 minutes.